The human body, mind, and spirit go through a cycle of change and growth every 7 years.
At age 7, the body is still developing and the mind is open to learning new things.
At age 14, the body is going through puberty and the mind is questioning authority and forming its own beliefs.
At age 21, the body is fully developed and the mind is focused on finding its place in the world.
At age 28, the body begins to decline and the mind is focused on settling down and starting a family.
At age 35, the body and mind are both in their prime and the spirit is focused on personal growth and spiritual development.